It’s snuggle time, and your pup is wrapped up in a blanket on your lap, enjoying the scritches. As your fingers work their way around their ears and neck, you feel something you don’t remember being there before: a small, pink bump. Where did that come from?
Finding a new lump on your dog can be alarming, and any veterinarian will be quick to warn you to check out any lumps or bumps that pop up on your dog to rule out skin cancer; fortunately, not every new bump means cancer.
A pink, button-like bump may be a histiocytoma, a common benign growth that often appears suddenly and eventually goes away on its own. Still, you can’t tell what a lump is just by looking at it. Here’s how to recognize the typical signs of a histiocytoma, what to expect if your dog has one, and why it’s important to have any new lump checked by your veterinarian.
What is a Histiocytoma in Dogs?
A histiocytoma is a benign (non-cancerous) growth that gets its name because it originates from histiocytes, which are immune cells that live in the skin. The skin is a busy organ that undertakes many jobs on a daily basis. One of those jobs is the constant sampling of the environment for things like microbes, irritants, and allergens.
Certain cells, known as Langerhans cells, are responsible for sampling environmental proteins and presenting them to the immune system to decide if they are friends or foes. Sometimes those Langerhans cells become overly zealous at reproducing and create small, red, raised button tumors known as histiocytomas.
Fortunately, a normal immune system quickly recognizes the overgrowth of Langerhans cells as bad and starts to take care of the tumor on its own. This means most histiocytomas only have a lifespan of a couple of months and don’t require further treatment.
Causes and Risk Factors for Pink Lumps on Dogs
Histiocytomas, sometimes called button tumors, can pop up on any dog, no matter the age, breed, or genetic makeup, but as with most types of growth, they have their own special preferences.
What Age Do Dogs Get Histiocytomas?
Histiocytomas are most common in young dogs, particularly those under three years old. Researchers don’t fully understand why age plays such a significant role. Because histiocytomas arise from immune cells in the skin called Langerhans cells, the developing immune systems of young dogs may play a role, but the exact cause of these tumors is still unknown.
Breeds Prone to Button Tumors
Certain breeds seem to pop up with histiocytomas on a more regular basis, suggesting that there is a genetic component. Though we don’t completely know what the correlation is, breeds that are most commonly affected include:
Dachshunds
Staffordshire Terriers
Symptoms of Histiocytoma in Dogs
You’ll most likely discover a histiocytoma while petting or grooming your dog. These growths tend to appear suddenly and are usually easy to spot once they’ve developed. Signs may include:
A small, round, raised bump on the skin
Pink to bright red coloring
Rapid growth over the first few weeks
Hair loss over or around the bump
Licking, chewing, or rubbing if the area becomes irritated
Bleeding, crusting, or an open sore if the bump becomes ulcerated
Visual Identification of Histiocytomas in Dogs
Histiocytomas can change in appearance over time, so describing them simply as small, pink bumps doesn’t tell the whole story. Here’s what you may notice as a histiocytoma develops and eventually regresses.
Initial Phase (Week 1-2)
If you happen to notice the bump in this phase, it will be nothing more than a small red or pink lump smaller than the width of a pencil eraser.
Growth Phase (Week 2-4)
Within a mere few weeks, these rapidly growing bumps can become anywhere between 2-4 centimeters in diameter. Some will be even larger.
Ulceration Phase (Week 4-8)
Though non-cancerous, histiocytomas can still cause trouble. As the tumor grows, it can be irritating, leading your dog to lick or chew on it, potentially causing bleeding and ulceration.
Regression Phase (Week 8-12)
Histiocytomas come from the immune system but also get destroyed by it. Within a couple of months of noticing it, you should start to see the tumor progressively getting smaller, with most disappearing by about three months.
Common Locations of Histiocytomas in Dogs
Histiocytomas in dogs are typically solitary rather than forming in groups, and they prefer the front half of the body. The head, especially the ears, lips, and nose, is the most common site for dog histiocytomas. The front legs and paws are also common spots for them, but keep in mind that histiocytomas in dogs can show up anywhere.
When Do Pink Tumors on Dogs Need Veterinary Attention?
I can’t stress this enough: have every new lump or bump checked out by your veterinarian, even if you’re sure it’s a histiocytoma or other benign growth, like a lipoma. None of us possess cytological vision, so what may outwardly appear as a non-cancerous bump may actually be something worse.
You’ll especially want to get your vet involved if the bump appears suddenly, grows rapidly, or changes shape, color, or texture.
Diagnosis of Histiocytomas in Dogs
Your vet is going to start with a thorough exam to not only look at the new bump, but also check for any other bumps that you may not have noticed. They will then take a sample of the bump in order to determine the composition. This can be done through a fine-needle aspirate or biopsy. Depending on the size and location of the growth, your veterinarian may recommend removing the entire lesion and submitting it for histopathology.
Mast cell tumors, malignant (cancerous) histiocytomas, and even melanomas can take on the look of a histiocytoma, so it’s important to get a real diagnosis before you decide to wait and see what happens.
Dog Histiocytoma Treatment
Once you have a definitive histiocytoma diagnosis, most vets will recommend the watch-and-wait approach, meaning you’ll monitor the bump at home while the immune system does its work.
While you wait, you’ll want to keep an eye on the area to make sure the tumor isn’t changing unexpectedly and that your dog isn’t bothering it. A light wrap or e-collar may be necessary to prevent secondary trauma from licking or chewing.
For histiocytomas that are especially irritating or bleeding a lot, surgical removal may be recommended.
Can You Prevent Pink Tumors on Dogs?
Histiocytomas can’t be prevented in any real way, but noticing new growths early means your veterinarian can identify them and rule out other conditions that may require treatment. Pay close attention to your dog’s body when grooming, petting, or playing and report any abnormalities to your vet.
Keeping up on regular veterinary care is the best thing you can do for histiocytomas and other tumors.
Protecting Your Dog’s Health with Pet Insurance
You can’t tell whether a lump is harmless just by looking at it, which means getting answers often requires diagnostic testing and, in some cases, treatment. Embrace pet insurance for dogs can help you focus on getting your pup the help they need, rather than worrying about finances. Costs vary widely depending on where you live, your veterinary clinic, and the testing or treatment your dog needs. You may encounter expenses such as:
A fine-needle aspirate (FNA) with cytology may cost around $150–$400.
Laboratory analysis of a biopsy may add approximately $200–$400 to the cost of the procedure.
If a histiocytoma becomes irritated or doesn’t regress, surgical removal may cost approximately $500–$1,500 or more, depending on the size and location of the growth and what’s included in the procedure.
Regular wellness exams are also an important part of keeping tabs on your dog’s overall health and can give your veterinarian another opportunity to spot new lumps or other changes. Embrace offers an optional wellness plan that can be added to your insurance plan to help you budget for routine care expenses such as wellness exams, vaccinations, preventive medications, and even grooming.Protecting Your Dog’s Health with Pet Insurance
You can’t tell whether a lump is harmless just by looking at it, which means getting answers often requires diagnostic testing and, in some cases, treatment.
Embrace pet insurance for dogs can help you focus on getting your pup the help they need, rather than worrying about finances.
Costs vary widely depending on where you live, your veterinary clinic, and the testing or treatment your dog needs. You may encounter expenses such as:
A fine-needle aspirate (FNA) with cytology may cost around $150–$400.
Laboratory analysis of a biopsy may add approximately $200–$400 to the cost of the procedure.
If a histiocytoma becomes irritated or doesn’t regress, surgical removal may cost approximately $500–$1,500 or more, depending on the size and location of the growth and what’s included in the procedure.
Regular wellness exams are also an important part of keeping tabs on your dog’s overall health and can give your veterinarian another opportunity to spot new lumps or other changes. Embrace offers an optional wellness plan that can be added to your insurance plan to help you budget for routine care expenses such as wellness exams, vaccinations, preventive medications, and even grooming.